6 Answers
6

Wow, I find it unusual that nobody mentioned the best tool around (my opinion) to do high quality Latex schematics (not too hard to learn, best circuits guaranteed) - it's Circuit_macros which are created and maintained by professor J. D. Aplevich.

Examples can be found here, and helpful installation tips are here. You can find manual in every Circuit_macros distribution. Commands for drawing are those of pic drawing language, and macros for electrical elements are written in m4 macro language. After writing down schematic in this combination of languages (pic, m4), file should be preprocessed with m4 macro processor leaving pure pic drawing behind. .pic. file is after that easily transfered in PSTricks or TiKZ/PGF (first couple pages of manual).

One thing that makes Circuit_macros so much more usable and faster is Cirkuit program (written by Matteo Agostinelli), in which you have the ability to preview the schematic while you are drawing it. There are always binaries around for Linux (although probably not for newest version), so the installation is straightforward. Here's how it looks like when you're using Cirkuit to draw schematics.

Problem with processing every following schematic with m4 and dpic manually, can easily be avoided using special LaTeX command \mtopgf defined on the 5th page of the manual.

Not exactly what you asked for, but in my larger projects, I've gotten a good mileage out of caching the compiled versions of tikz figures. It is discussed in the tikz documentation in the chapter named “Externalizing graphics”, and discussed further here: Script to automate externalizing tikz graphics

This would take care of the slowness of, say, circuitikz, by having you compile each circuit once, and subsequently including it instead.